While the study of dinosaurs and the reconstruction of skeletons are both important areas of paleontology, they are by no means the only ones. Paleontology is nothing less than the study of life on earth, from its origin to the present day. This includes on the one hand all the diversity of life, from bacteria to kelp to dinosaurs. Paleontology also spans many areas of science -- paleontologists must have training not only in biology, but in geology, chemistry, and other fields as well. Because paleontology is such a diverse field, several subdisciplines are recognized. Each of these focusses more closely on particular kinds of organisms,preservation types, or techniques.

Paleontogy Paleontology is the study of fossils. A fossil is defined as any trace of a past life form. Thus, although wood, bones, and shells are the most common fossils, under certain conditions soft tissues, tracks and trails, and even coprolites (fossil feces) may be preserved as fossils. Although most of the fossils that paleontologists study are several thousands to several billions of years old, there is no absolute minimum age for a biological structure to be a fossil.

Paleontologists study these fossils and attempt to use them to reconstruct the history of the Earth and the life on it. Some study the ecology of the past; others work on the evolution of fossil taxa.

The first people to record their speculations on these strange rocks that took the form of plants and animals were Greek philosophers. The oldest recorded statement that suggested fossils may be the remains of once-living creatures was made by Xanthos of Sardis in about 500 B.C.Aristotle (384 B.C.) suggested that fossils of fish were remnants of sea animals that swam into cracks in rocks, and were stranded there. These early speculations were held for more than 2000 years, with no improvements or additions to these theories. In this time, the Roman civilization surpassed that of the Greeks, and itself passed into the intellectual night of the Dark Ages.

By the middle of the eighteenth century, the similarity of fossils to some currently living organisms had convinced many naturalists that these mysterious stones were the remains of plants and animals that had somehow been preserved within rocks.
The more perceptive of these put forward the idea that the sea must have once covered larger areas in order for marine fossils to be deposited so far inland. Most people at the time attributed them to the Biblical Flood: however, palentologists during the early nineteenth century discovered evidence which caused the flood theory to fold. A succession of sedimentary rocks revealed a progression of lifeforms which could not be the result of a single catastrophe: the ages of the sedimentary beds meant that the fossils had been formed over periods covering tens of thousands, if not millions of years!

By the beginning of the nineteenth century, the controversy was over. The consensus was that fossils were remnants of organisms that had lived in the distant past. The groundwork had been laid for the recognition of fossils as evidence of evolution.

Note: I've intentionally used the North American spelling of Paleontology vs. Palaeontology to make referencing this and related nodes easier.